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R. A. MCCANN. l RAILWAY SIGNALING.

APPLICATION FILD DEC-4 1917.

R. A. McCANN.

' RAILWAY SIGNAUNG.

APPLICATION FILED DEC-4, 911.

Patented Nov. 18, 1919.

2 SHEETS-SHEET 2.

,INVENTOR Swissvale, in the county UNITED STATES PATENT OFFICE.

RONALD A. MCCANN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO TI-IE UNION SWITCH & SIGNAL COMPANY, 0F SWISSVALE, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

RAILWAY SIGNALING.

Specification of Letters Patent.

Patented N 0V. 18, 1919.

Application filed December 4, 1917. Serial No. 205,429.

To all whom t may concern:

Be it known that I, RONALD A. MCCANN, a citizen of the United States, residing at n of Allegheny and State of Pennsylvania, have invented'cer-A tain new and useful Improvements in Railway Signaling, of which the following is a specification.

My invention relates to railway signaling, and particularly to signaling forv single track over which traffic moves in both direc: tions. More specifically, my invention re-` lates to means for controlling thevsignals adjacent the passing sidings in systems of the type specified. n

I will describe two forms of signaling embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a view showing one arrangement of signals to which my invention may Ibe applied. Fig. 2 is a diagrammatic view showing one arrangement of apparatus and circuits for the control of signal 5 in Fig. 1 and em= bodying my invention, the arrangement shown in this view being particularly well adapted to systems employing direct current as the controlling and operating energy. Fig. 3 is a diagrammatic view showing ya modification of the apparatus and circuits shown in Fig. 2 and also embodying my invention, the arrangement shown in this View being particularly well adapted to signaling systems in which alternating current is the controlling and operating energy.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the reference character 15 designates the track rails of a portion of a single track railway, which isr divided by passing sidings M, N and O into two stretches A-D and E-H. Stretch A-D is further divided by insulated joints 2, into a number of blocks, A-l5 I S-C and C-D, while stretch E--H is similarly divided into blocks E-F, F-G and G-H.

Tratlic through the stretch E-H from east to west is governed by a plurality of signals 1, 3 and 5, While traffic through this saine stretch in the opposite' direction isgoverned by signals 4, 6 and 8. Stretch A-D is similarly provided with signals 9, l1, 13, 12, 14 and 16. The passing siding' N is protected. by signals 7 andy 10. As here shown,

-hereinaften It is desirable,

oa pair of opposing signals is located adjacent each end of each block, although I do not desire to be limited to this particular location and distribution of the signals.

- The signals for stretch A-D are so controlled that when a train moving toward the east enters this stretch, signal 9 is placed at stop and is held there until the train passes out of the stretch, thus prohibiting a westbound train from entering the stretch while the stretchis occupied by the eastbound train. As the eastbound train enters the stretch, it also causes signal 16 to indicate stop and as it passes signals 14 and 12 these signals are similarly caused to change to stop indication. When the en tire train passes out of 'block A-B, signal 16 changes to the caution indication, and when the entire train passes out of block B-C, this signal returns to the full proceed indication. Signal 14 changes to caution when the train leaves block BeC, and to proceed when the train leaves block C-D. Two or more trains may, therefore, follow each other through the stretch under the same signal protection as is customarily provided on double track roads. Similarly, when a westbound train enters stretch A-D, signals 9,- 12, 14 and 16 are placed at stop, and signal 9 subsequently changes successively to caution and proceed. Signal 11 changes to stop when it is passed by the train, and subsequently changes tc caution and proceed successively.

The signals for stretch EkH are controlled in the same manner as the signals for stretch A-D.

The operation of the signals which I have just outlined may be accomplished by several different arrangements of apparatus and circuits, such, for example, as the arrangements sho-wn in Letters Patent of the United States Nos. 1,204,998V and 1,233,488, granted to me on November 14, 1916, and on July 17, 1917, respectively. I do not wish to be limited, however, to any particular arrangements of apparatus and circuits for accomplishing this signal operation.

ienever signal 9 indicates stop, signal 7, of course, indicates cautio1i,7 and whenever signal 7 indicates stop, signal 5 indicates caution The manner in which this control is accomplished will be explained however, that when an eastbound train occupies stretch rs1-D, signa-l 5 as well as signal 7 should indicate caution, but that when a westbound train has passed signal 9, thus allowing signal 7 to change to caution, signal 5 should return to the full proceed position. The reason for this is as follows: Assume that signal 5 indicates proceed while signal 9 is at stop, and that two trains inoving in opposite directions approach siding N. lf the eastbound train should pass signal 9 just after the westbound train had passed signal 5 (indicating proceed), the westbound train would receive a stop indication at signal 7 without having been previously warned by a caution indication at signal 5. However, if two westbound trains are nioving along the track between A and H, it is desirable that signal 5 should change to proceed indication as soon as the first train has passed signal 9, in order to avoid any unnecessary delay to the second train by a caution indication at signal 5.

The object of the present invention is the provision of novel and simple means for accomplishing the desired control of signal 5.

Referring now to Fig. 2, the niain track of the siding N is provided with a track circuit coniprising a battery 510 and a track relay T10. Block E-F is divided into two sections provided with a track circuit comprising batteries 5S and 125 and track relays TS and T 5.

Signal 7 is controlled 'by a signal relay R7, which is responsive to reversals of current. The caution indication circuit for this signal is from battery Z7 through wires 17, 18, 19 and 20, neutral contact 21 of relay R7, wire 22, signal 7, wire 23, neutral contact 24 of relay R7, and wires 25, 26, 27 and 28 to batteryZ7. The proceed indication circuit for this signal isthe saine as the caution circuit up to and including contact 21, then through wire 29, polarized contact 30, wire 31, signal 7, thence as before to battery Z7. Signal 7, consequently, indicates proceed when relay R7 is energized in such direction as to close contact (which 1 will Call the normal direction of energization), caution when the relay is energized in the reverse direction, and stop when the relay is denergized.

Signal 5 is similarly controlled by a signal relay R5, the caution circuit for this signal including neutral contacts 32 and 33, and the proceed circuit including a contact 34 which is closed when the relay is energized in normal direction but not in reverse direction.

Signal relay R7 is provided with a circuit which is controlled by the track relay T17 and by a pole-changer W operated by signal 9, this pole-changer being reversed while the signal is moving between the stop and cau- EK and 1li-F, each of which is tion positions. This circuit, when the polechanger is in the position shown, is from battery Z9 through wire 35, pole-changer lll, wires 36 and 37, contact 38, wire 39, relay R7, wire 40, pole-changer W7, wire 41 to battery Z7. `When signal 9 indicates proceed or caution, relay R7 is energized in the nornial direction so that signal 7 then indicates proceed; but when signal 9 indicates stop, relay R7 is energized in the reverse direction, so that signal 7 then indicates caution; assuming, of course, that block D-E unoccupied.

Signal relay R5 is provided with a circuit which is controlled by a pole-changing relay P, the contacts of which constitute a pole-changer for reversibly connecting relay R5 with battery Z7 according as relay P is energized or denergized. When this relay P is energized, as shown, the circuit for relay R5 is from battery Z7 through wires 17, 18 and 44, contact 42, wire 45, contact 46 of track relay TS, wire 47, contact 48 of track relay T5, wire 49, relay R7, wire 50, contact 43, wires 51 and 28 to battery Z7. lV ien relay P is energized, relay R5 is energized in normal direction so that signal 5 indicates proceed, but when relay P is denergizcd, relay R5 is energized in reverse direction, so that signal 5 indicates caution; assuming, of course, that block E-F is unoccupied.

Pole-changing relay P is provided with a circuit which is froni battery Z7 through wires 17, 18, 19 and 20, contact 21, wire 29, contact 30, wire 52, contact 53N of a relay J, wire 54, contact 55, wire 56, relay P, wires 57, 27 and 28 to battery Z7. Contact 55 is operated by signal 7 and is closed while this signal is in clear or caution position or at any point between these two positions. Assuming, then, that contact 53N is closed, relay P will be energized when relay R7 is energized in norxnal direction but not when energized in the reverse direction, this selection being accoinplished by polar contact 30 of relay R7.

It follows from the foregoing that with only the apparatus thus far described, whenever signal 9 indicates stop, signal 5 will indicate caution, because relay P will be deenergized due to the reverse energization of relay R7.

Relay P is provided with another or aux iliary circuit, which is controlled by contact 53R of relay J, this circuit being froin battery Z7 through wires 17 and 58, contact 53H, wire 54, contact 55, wire 56, relay P, wires 57 27 and 28 to battery Z7. Consequently, when contact 53R is closed, relay P will be energized when relay R7 is reversely energized (Contact 55 being closed when signal 7 indicates caution), and so signal 5 may then indicate proceed while signal 9 indicates stop.

Relay J is a directional relay,'its contact 53N or 537 being closed according as the relay is energized in normal or reverse direction. Furthermore, when either contact is closed such contact remains closed until the relay is subsequently energized in the opposite direction, even though the relay may in the meantime become denergized. This relay is provided with a reverse energizing circuit which is from the right-hand terminal of batter f Z7 through wires 28, 27, 26 and 59, contact 60, wire 61, back point of contact 62, contact 63, wire 64, relay J, wire 65 to middle point of battery Z7. This circuit is closed momentarily when a train moving toward the west enters block D-E, because the back point of contact 62 of relay R7 then closes and contact 60 is closed momentarily while signal 7 is moving toward stop position;

Relay J is also provided with anormal energizing circuit for restoring its contact to the position shown, this circuit being from the left-hand terminal of battery Z7 through wires 17, 18, 19 and 66, contact 67, wire 68, front point of contact 62, contact 63, wire 64, relay J, wire 65 to the middle point ot' battery Z7. Contact 67 is closed when signal 7 indicates caution, hence this circuit is closed momentarily when relay R7 becomes energized in normal direction and before signal 9 leaves the caution position, that is, when the westbound train passes signal 11 in Fig. 1.

The operation of the system shown in Fig. 2 is as follows:

When there is no train on the track between points A and F in Fig. 1, the parts of the apparatus are in the positions in which they are shown in Fig. 2, so that signals 9, 7 and 5 indicate proceed. If, now, a train moving toward the east enters stretch AfB, it causes signal 9 to change to stop indication. This movement of signal 9 reverses pole-changer `W so that signal relay R7 becomes energized in the reverse direction, thus causing signal 7 tochange to caution position. This reversal of relay R7 causes pole changing relay P to become denergized because Vof the opening of contact 30, thus reversing the direction in which relay R5 is energized whereby signal 5 changes to the cautionposition. The signals remain in these positions until the train enters block DhE, whereupon signal 7 changes to the stop position because relay R7 becomes denergized due to the opening of contact 3S or track relay T10. As the train enters block E-F, signal 5, of course, changes to the stop position, due to the opening of relay R5.

T will now assume that the track between A and F'is unoccupied and that a train moving toward the west enters block E-F. The consequent opening of track relay T5 causes relay R5 to become denergized whereby signal 5 changes to the stop position. As the train proceeds through the block E F, track relay TS opens and track relay T5 closes, but this causes no change in the condition of the apparatus( As the train enters the block D-E, it opens track relay T10, which in turn denergizes relay R7 whereby signal 7 changes to the stop7 position. uring this movement of signal 7, contact 60 is closed momentarily, thus closing the reverse energization circuit for' relay J. Contact 53H ofthis relay then becomes closed instead of 53N. When the entire train has passed out of the block E-F, track relay TS closes, thus causing relayR.5 to become energized, but this relay is then energized in the reverse direction because relay P is denergized, due to the fact that its circuit is openedat contact 55. Signal 5, therefore, assumes the caution7 position. As the train passes into block C-D it causes signal 9 to change to the stop position, so thaty when track relay T10 closes, relay R7 becomes energized in the reverse direction, thus causing signal 7 to move to the caution position. Contact 55 then becomes closed, thus closing the auxiliary circuit tor relay P because this circuit does not include contact 30 of relay R7. The consequent energization of relay P causes relay R5 to be energized in the normal direction, so that signal 5 changes to the proceed position. Then the train passes signal 11 in Fig. 1, signal 9 moves to cautiom and the consequent reversal of pole-changer W causes relay R7 to become energized in the normal direction. The normal energizing circuit for relay J is then closed momentarily at contacts 67, 62 and 63, so that this relay is restored to its normal position wherein contact 53N is closed. The reversal of relay R7 causes signal 7 to change to the proceed7 position. The parts of the apparatus are then in the positions in which they are shown in the drawing, except that signal 9 is at caution This signal, of course, will change to the proceed7 position as soon as the train passes signal 13 in Fig. 1.

Referring now to Fig. 3, the system here shown is similar to that shown in Fig. 2, except for certain changes which are desirable on account of the substitution of sources of alternating current for the batteries shown i'n Fig. 2. It is understood that the primary winding of each transformer U, U5, U7 and U9 shown in Fig. 3 is connected with a suitable source of alternating signaling current. The two track circuits for block E F in Fig. 2 are replaced by a single center-fed track circuit in Fig. 8, the source of current for such track circuit being transformer U. As for block D-.E, the single track circuit shown in Fig. 2 is replaced by a. center-fed track circuit in Fig. 3, thus introducing an additional track renected with the secondary of transformer U7, the primary circuit of transformer X including switch-operated contacts 83 and 84 for a purpose hereinafter explained.

Signal relay R7 comprises a pair of contacts 21 and 2l which are swung to the right or .left according as the relay is energized in the normal or the reverse direction, and which occupy intermediate positions when the relay is deenergized. The caution indication circuit for signal 7 is closed when relay R7 is energized in the reverse direcvtion, this circuit being from secondary of transformer UT through wires 17, 18, 19 and 29, lett-hand point of contact 21, wire 29, signal 7, wire 23, left-hand point of Contact 24, kwires 25, 26, 27 and 28 to the secondary of transformer U7. lThe proceed indication circuit for this signal is closed when relay R7 is energized in the normal direction, this circuit being from transformer U7 through wires 17 18, 19 and 20, right-hand point of contact 21, wire 22, signal 7, wire 28, right-hand point ot' contact 2a, wires 25, 2G, 27 ann 28 to transformer U7.

Signal 5 is controlled in a similar manner by signal relay R5.

Relay P is provided with a circuit which passes from the secondary of transformer U7 through wires 17, 18, 19, 2O and 78, righthand point of contact 79 ofrelay R7, wire 85, back point or' contact 69 of relay Ja, wire 5a, contact 55, wir@ 56, relay P, and wires 57 and 28 to transformer U7. Assuming, then, that the back point of contact 69 is closed, and that contact 55 is closed, relay P will be energized when relay R7 is energized in normal direction but not when relay R7 is energized in the reverse direction, this selection being accomplished by contact 79 of relay R7. Relay P is provided with an auxiliary circuit, which is closed only when relay Ja is energized, this circuit being from transformer U7through wires 17, 18 and 70, front point of contact G9, wire 5%, contaclJ 55, wire 56, relay P and wires 57 and 28 to transformer U7. Consequently, when relay J is energized and contact 55 is closed, relay P will be energized if relay R7 is reversely energized, and so signal 5 may then indicate proceed while signal 9 indicates stop Relay Ja is provided with an energizing circuit which passes from the secondary of transformer U7 through wires 17, 18, 19, 71 and 72, contact 73, wire 7l,back point of contact 75 of track relay T7, wire 76, relay Ja, wires 7 7 27 and 28 to transformer U7. This circuit will be` closed when train moving toward the west enters block D--E, but will immediately be opened' at contact 7 3 when signal 7 moves away from the proceed position. Relay J when once energized, is held energized by a holding circuit which is from transformer U7 through wires 17 18, 19, 2O and 78, contact 79, wire 80, Contact 81, wire 82, relay J and wires 77, 27 and 28 to trans former U7. This circuit is closed at contact 79 when relay R7 is deenergized or is energized in the reverse direction.

The operation of the system shown in Fig. 8 is similar to that shown in Fig. 2; consequently, a few brief remarks concerning this operation will be sutlicient. As a train moving toward the east enters stretch A-D in Fig. 1, the consequent movement of signal 9 to danger position reverses the direction of cnergization oi relay R7 and so opens at contact '79 the circuit for relay P. The decnergization ci? relay P, of course, reverses the direction of cnergization of relay so that signal 5 moves to the caution position.

dien a train moving toward the west enters block D-E, it opens track relay 'P7-and so closes the energizing circuit for, relay J a. is soon as contact 79 of relay R7 reaches its intermediate or deenergized position, the holding circuit for relay Ja is closed. Consequently, when the train passes out of block D-E and signal 7 has moved to the caution position, relay P becomes energized so that signal 5 moves to the proceed position. After the train passes signal 11 in Fig. 1, relay R7 becomes energizedin the normal direction so that contact 79 opens the holding circuit for relay J whereupon this relay becomes deenergized.

its has been pointed out hereinbefore, the primary circuit for transformer X is controlled by switch operated contacts 83 and 81. Contact 83 is operatively connected with switch 85 and is closed when this switch is set for the straiglit track but opened when the switch is set for the siding. Contact SelA is similarly operated by switch 85. The

'reason for including these contacts in the transformer circuit is as follows: First, assuming` that the primary o transformer X were always connected with a source of current and that a .train moving toward the west enters the siding N, it will be seen that when such train occupies the portion of the siding between points 2a and 2b, relay J7 would become denergized. Then, if the train should proceed ont on the main track through switch 86 and pass signal 9, relay Ja would continue to be denergized so that signal 5 would be held in the caution position until theJ train passes signal 11 in Fig. 1. By including contact 83 in the circuit for transformer X, the operation becomes as follows: As the west-bound train enters the siding and passes beyond point 2b, relay J becomes denergized, but when switch 8G is reversed to allow this train to pass out on to the main track, track relay T7 becomes deenergized and so closes the energizing circuit for relay Ja. Relay R7 is, of course, then denergize'd so that the holding circuit for relay J2L is closed. It follows, then, that after the t ain passes signal 9, relay P will become energized so that signal 5 will move to the proceed position.

IVhere in the accompanying claims I have used the expression a portion of railway track comprising three successive blocks, the blocks referred to are blocks E-F,D-E and C`-D, these blocks being the first, second and third blocks respectively. The signals for -the first and second blocks are signals and 7 respectively. v

Although I have herein shown and described only two `forms and arrangements of apparatus and circuits embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described iny invention, what I claim is:

1. In combination, a portion of railway track comprising three successive blocks, a first and a second signal for theiirst and second blocks respectively, a signal relay for controlling said second signal, a stick relay, means controlled by said signal relay and by a train passing along said track from the first block toward the third for energizing said stick relay and holding it energized until the train leaves the third block, said stick relay remaining denergized during the passage of a train in the other direction, and means controlled by said stick relay and by said signal relay and operating when the signal relay is in such condition that the second signal indicates caution to cause the first signal to indicate proceed or caution according as the stick relay is energized or deenergized.

2. In combination, a portion of railway track comprising three successive blocks, a first and a second signal for the first and second blocks respectively, a first and a second signal relay for controlling said first and second signals respectively and each responsive to reversals of current whereby each signal indicates proceed or caution according as the corresponding signal relay is energized in normal or reverse direction, traincontrolled means for causingthe second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in the third section, a polechanging relay for controlling the signal relay for the first signal whereby such signal relay is energized in normal or reverse direction according as the pole-changing relay is energized or denergized, a directional relay controlled by train movements and occupying a normal'position when the second and third blocks are unoccupied but a reverse Iposition while a train moving in the direction of traffic governed by said signals, occupies the second and third blocks, andl`r` means controlled by said directional relay and said second signal relay for energizing said pole-changing relay only when the second signal relay is energized in normal direction if the directional relay is normal, but

for energizing the pole-changing' relay when the second' signal relay is reversely energized if the directional relay is reversed.

3. In combination, a portion of railwaytrack comprising three successive blocks7 a first and a second signal'for the first and second blocks respectively, a first and a second signal relay for controlling said iirst and .second signals respectively and each responsive to reversals of current whereby each signal indicates proceed or caution according as the corresponding signal relay is energized in normal or reverse direction, traincontrolled means for causing the second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in the third block, a pole- `changing relay for controlling the signal relay for the first signal whereby such signal relay is energized in normal or reverse direction according as the pole-changing relay is energized or denergized, means controlled by the second signal relay for energizing the pole-changing relay when the second signal relay is energized in normal direction but not when it is energized in reverse direction whereby the presence of a train upon the third block moving toward the first will cause the first signal to indicate caution, and means controlled by a train moving in the other direction for causing` said pole-changing relay to be energized when the second signal relay is energized in reverse direction whereby when such latter train occupies the third block the first signal will indicate proceed.

4. In combination, a portion of railway track comprising three successive blocks, a first and a second signal for the first and second blocks respectively, a first and a second signal relay for controlling said first and second signals respectively and each responsive to reversals of current whereby each signal indicates proceed or caution according as the corresponding signal relay is energized in normal or reverse direction. train-controlled means for causing the second signal relay to be energized in reverse or normal direction according to the presence or absence of a train in the third section, a polechanging relay for controlling the signal relay for the first signal whereby such signal relay is energized in normal or reverse direction -according as the pole-changing relay is energized or denergized, means controlled by the second signal relay for energizing the pole-changing relay when the second signal relay is energized in normal direction but not when it is energized in reverse direction whereby the presence of a train upon the third block moving toward the lirst Will cause the first signal to indicate caution, a stick relay, means controlled by said stick relay When energized for causing said polechanging relay to be energized when the second signal relay is energized in reverse direction, and means controlled by a train movino 'in the direction of traliic governed by said signals for energizing said stick relay when the train enters the second block and for keeping it energized while the train occupies the second and third blocks7 whereby when such latter train occupies the third block the first signal will indicate proceed.

5. In combination, a portion of' railway track comprising three successive blocks, a first and a second signal for the irst and second blocks respectively, a first and a second signal relay for controlling said first and second signals respectively and each responsive to reversals of current whereby cach signal indicates proceed or caution according as the corresponding signal relay is energized in normal or reverse direction, traincontrolled means for causing the second signal relay to be energized in reverse or nor mal direction accordingl to the presence or absence of a train in the third block, a polechanging relay for controlling the signal relay for the irst signal whereby such signal relay is energized in normal or reverse direction according as the pole-changing relay is energized or denergized, means controlled by the second signal relay for energizing the pole-changing relay when the second signal relay is energized in normal direction' but not when it is energized in reverse direction Awhereby the presence of a train upon the third block moving toward the first ivill cause the lirst signal to indicate caution7 a directional relay for causing said polechanging relay to be energized when the second signal. relay is reversely energized, and means controlled by a train moving along said track in the direction in which said signals govern tratlic for causing operation of said directional relay.

In testimony whereof I affix my signature in presence of two Witnesses.

RONALD A. MCCANN.

Vitnesses:

A. HERMAN VVEGNER, E. P. CRUM. 

